Polyolefin composition stabilized with hydrazones



United State P t 3,407,174 .I POLYOLEFIN COMPOSITION STABILIZED WITHHYDRAZONES Tsuneto Kuriyama, Chikujyo-gun, andToshinhiko Kuroda, ShigeruTanba, and Isao Toshima, Yokkaichi-shi, Japan, assignors to YoshitomoSeiyaku Kabushiki Kaisha, Osaka-shi, and Mitsubishi PetrochemicalCompany Limited, Tokyo, Japan No Drawing. Filed Feb. 5, 1965, Ser. No.430,730 Claims priority, application Japan, Feb. 7, 1964,

39/ 6,043 8 Claims. (Cl. 260-453) This invention relates to stabilizedpolyolefin compositions. The present invention has it as an object toprovide a polyolefin composition having a high degree of stabilityagainst oxidation deterioration accelerated by the contact of thepolyolefin or specifically polypropylene with copper.

Polypropylene is so high in the stress-crackproofness,thermoembrittlementproofness, softening point and electric insulation asto be adapted to uses as an electric wire coating material. But the factthat it is so sensitive to the action of heat or light in the presenceof oxygen as to be deterioriated and denaturalized is a great obstaclein its expected uses. It is already known to add such additive as anantioxidant of a phenol, amine or sulfur series with a view to improvingsuch deterioration and denaturalization and satisfactory results havebeen obtained. However, even in the case of stabilization by such knownadditive as mentioned above, if it is used in contact with copper, itsstabilizing effect will markedly decrease and usually it will not beable to substantially improve the deterioration and denaturalization.

The present invention is to provide a polyolefin composition highlystabilized against deterioration by heat oxidation even in the presenceof copper.

We have found that, when a small amount of an azine compound is addedtogether with a general stabilizer to a polyolefin, the polyolefin willkeep a high degree of stability even in contact with copper, and we havereached the present invention on the basis of this finding. That is tosay, the polyolefin composition of the present invention contains anazine compound having the general formula wherein R R R and R arehydrogen or same or different hydrocarbon radicals which are substitutedor unsubstituted alkyl, cyclo'alkyl, aryl, alkaryl or aralkyl radicals,in an amount of 0.01 to preferably 0.1 to 3% by weight to the polyolefinand contains also any other stabilizer.

An object of the present invention is to provide a polyolefincomposition having a high degree of stability against deterioration byheat oxidation even in contact with copper.

As the azine compounds which may be used in the present invention, thereare mentioned 2,4-dihydroxyacetophenone azine, 2,4-dihydroxyoctaphenoneazine, 2,4- dihydroxypropiophenone azine, 2,4 dihydroxybutyrophenoneazine, 2,4-dihydroxycaprophenone azine and 2,4- dihydroxydodecanophenoneazine.

In the polyolefin composition of the present invention, usually theabove mentioned azine compound and any of other general stabilizers areboth used, Such other stabilizers include all of such stabilizers as,for example, of

3,407,174 Patented Oct. 22, 1968 phenol, .amine and sulfur series andsuch stabilizers to stabilize the polyolefin against deterioration byheat or light oxidation as ultraviolet ray absorbents. Further, suchother additives to be mixed to improve the nature of the polyolefin ascoloring agents, fillers and carbon can be properly added The polyolefinso called in the present'invention means a polymer or copolyiner of sucholefin as ethylene, propylene, 3-rnethyl-butene-l, pentene-l, 4-methylpentenel, 3,3-dimethyl butene-l, 4,4-dimethyl butene-l, octene-l ordecene-l and a mixture of such polymer and copolymer.

In the present invention, as a method of mixing a component to be addedin a polyolefin or a polyolefin composition containing any otheradditive, it can be uniformly mixed by means of such proper mixer as,for example, a Bambury mixer, rolls or an extruder.

The present invention shall be explained more particularly withreference to an example in the following. However, the present inventionshould not be restricted by the following example.

Further, the test of deterioration by accelerated oxidation shown in theexample was carried out by measuring the time until a remarkablediscoloration or crack was observed in the sample at a temperature of C.by means of a TSS gear type ageing tester. Said time is known as anembrittling time.

Example To an isotactic polypropylene powder of an intrinsic viscosityof about 2.2 in tetraline at 138 C. were added 0.15%l,l,3-tri(2-methyl-4-hydroxy-5 t-butylphenyl) butane and 0.4%distearyl-3,3'-thiodipropionic acid as antioxidants and each of azinecompounds as a copper damage preventive. The thus obtained compositionwas melted with an extruder and was made pellets;

A sheet 0.5 mm. thick with a copper screen sealed in was made of suchpellets at 230 C, with stainless steel pressing plates. A small piece of3 x 6 cm. was cut off the sheet and was measured. (The copper wasexposed in the crosssection.)

For comparison, samples in which the same antioxidants were used but noazine compound was added or no copper screen was sealed, were alsomeasured. The results are shown in the following table.

Em- No. Azine compound Copper brittllng screen time 1. Absent Absent 6002 .do 40 3. 2,4dihydroxyaeetophenone azine, 0.5% do. 210 4-2,4dihydroXyoctaphenone azine, 0.5% do.. 280 5 2,4-dihydroxyaeetophenoneazine, 0.5% Absent 700 6. 2,4-dihydroxyoetaphenone azine, 0.5% do 620wherein R R R and R are hydrogen or same or different hydrocarbonradicals which are substituted or un- I 3 substituted ,alkyl, cycloalkylary l, radicals.

2. A polyolefin composition according to claim 1 wherein said azinecompound is used in an amount of 0.01 to 10%, preferable 0.1 to 3% byweight to the polyolefin.

3. A polyolefin composition according to claim 1 wherein said azinecompound is 2,4-dihydroxyacetophenone azine.

4. A polyolefin composition according to claim 1 wherein said azinecompound is 2,4-dihydroxyoctaphenone azine.

5. A polyolefin composition according to claim 1 wherein said azinecompound is 2,4-dihydroxypropiophenone azine.

6. A polyolefin composition according to claim 1 wherein said azinecompound is 2,4-dihydroxybutylophenone azine.

alkaryl or aralkyl 7. A polyolefin composition according to claim 1wherein said azine compound is 2,4-dihydroxycaprophenone azine.

8. A polyolefin composition according to claim 1 wherein said azinecompound'is 2,4-dihydroxydecanophenone azine.

' References Cited .UNITED STATES PATENTS 2,757,163 7/1956 Bowers260-459 2,786,044 3/1957 Warner et a1. 260 45.9 3,010,939 11/1961Dinsberg 2 60-45.9 3,110,696 11/1963 Dexter 260-45.9 3,142,658 7/1964Stewart 260-459 DONALD E. CZAJA, Primary Examiner.

H. E. TAYLOR, Assistant Examiner.

1. A POLYOLEFIN COMPOSITION OF SOLID POLYETHYLENE, PROPYLENE ORETHYLENE-PROPYLENE COPOLYMERS CONTAINING A STABILIZING AMOUNT OF ANAZINE COMPOUND HAVING THE GENERAL FORMULA